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Old Western pump issue

Discussion in 'Truck & Equipment Repair' started by JimRoss, Oct 23, 2009.

  1. JimRoss

    JimRoss Member
    Messages: 99

    A few years back I bought a 78 Chevy 3/4 ton with a Western 7 1/2' blade. Manual states it is a Isarmatic Mark IIIa pump/motor.

    I noticed last year the blade wouldnt lift up, without help, until it got cold out. The colder it got, the better the blade would lift. I just figured the oil was super old ( thined out ) and needed replacing. Since I only plow my own drive, I let it go until now.

    Today I drained/changed the oil ( used auto trans fluid like the manual stated ). Took 1.5 quarts. Problem is, the blade still isnt lifting. I can turn the blade side to side, it just wont lift ( unless I lift blade by hand while someone else uses the joystick ).

    I surely can not afford a whole new pump. Does it sound possible to fix this old one?

    Does it sound like the pump assemby needs replaced, or does it have something to do with the plunger ram?

    Is either something easy enough for a novice to change?

    Thank you for your help.

    Photos of the pump/motor assembly:
    [​IMG]
    [​IMG]
    [​IMG]
     
    Last edited: Oct 23, 2009
  2. drp

    drp Senior Member
    from ontario
    Messages: 170

    could be a cable adjustment. Rectangular plate for lift I believe. manually activate the valve while some body runs the pump.

    Or could be a week hydraulic pump, easy to replace and not to pricey.

    A manual for your unit can be found on westerns website.
     
  3. JimRoss

    JimRoss Member
    Messages: 99

    Since it lifts fine in super cold weather, I'm assuming it isn't a cable adjustment?

    Yes, this is sort of what I thought it could be, but didnt want to spend $140 and it not be the problem.

    I have the manual that came with the truck.
     
    Last edited: Oct 23, 2009
  4. drp

    drp Senior Member
    from ontario
    Messages: 170

    You mean the manual for the plow?

    Service manuals can also be found on Westerns site which might help you trouble shoot the issue.

    Running good cold seems odd. I would have expected the opposite if it is a pump problem. However the weak lift and still okay angle does sound like a week pump.
    It takes less pressure to angle than lift.
     
  5. JimRoss

    JimRoss Member
    Messages: 99

    I ment there was a small owners manual for the plow, when I bought the truck.

    My thoughts are if a pump seals are old and maybe cracked, the thin fluid by-passes the seals. When the fliud is cold and much thicker, it can not by-pass the seals. The colder it is out, the faster the plow will lift.

    I'm no machanic, just thinking outloud here.
     
  6. drp

    drp Senior Member
    from ontario
    Messages: 170

    http://www.westernplows.com/pdf/62880.pdf

    Mechanics service manual with trouble shooting guide and test and adjustment procedures.

    Hope this helps.

    These units are really very easy to work on with out the electronics of the newer units.
     
  7. drp

    drp Senior Member
    from ontario
    Messages: 170

    The ticker (cold) the fluid the slower the flow as the pump has to work harder to move it.
    At -20C my unit, which was the same as yours, would hardly move until the fluid warmed up.
     
  8. JimRoss

    JimRoss Member
    Messages: 99

    hmmm, wierd. Just the opposite of what mine is doing.

    Thanx for the manual. That will help, if I have to replace the pump. I'm hoping it's just the pump. While the manual makes it look fairly easy, I dont want to rebuild the whole thing if it isnt needed.
     
  9. drp

    drp Senior Member
    from ontario
    Messages: 170

    pump replacement is easy. Drain fluid. Remove battery cables remove two bolts holding the motor to the body. Lift of motor. Remove two bolts holding pump in place and remove pump and filter as a unit. New filter on new pump watch for o-ring on bottom when installing new pump. Now reverse disassemble to reassemble. Add fresh fluid. Takes about a half hour start to finish.
     
  10. Plowfixguys

    Plowfixguys Senior Member
    Messages: 222

    Jim its easy to test the pump when its in the power unit. If you have or can borrow a pressure gauge (2000 psi max is good) hook it up to the one of the angle ports and angle the plow (hoses disconnected). Watch the gauge and note the highest pressure achieved with the motor running. If you get 1600 to 1800 psi your pump is good, if not, check and or replace the o ring under the pump and retest. If you still cant get the correct pressure replace the pump.

    Good luck
     
  11. JimRoss

    JimRoss Member
    Messages: 99

    I dont have a guage available to me.

    I will take the pump out and check the o-ring under it. Just might be the gremlin I'm after.
     
  12. drp

    drp Senior Member
    from ontario
    Messages: 170

    Any luck so far?
     
  13. JimRoss

    JimRoss Member
    Messages: 99

    Sorry, I'm out of town for a week. I'll give the o-ring a try when I get back.
     
  14. JimRoss

    JimRoss Member
    Messages: 99

    UPDATE:

    Replaced O-ring under pump, no help.

    I have ordered a new pump. I will post results after it is installed.
     
  15. WeDoSnowplowing

    WeDoSnowplowing Senior Member
    Messages: 160

    I look at the Mechanics service manual. Looks like need to order a new one. Plunger Ram looks rusted good. That can eat away the seal. Get a completed pump. with a warranty
     
  16. Turf Commando

    Turf Commando Senior Member
    Messages: 567

    Have the same set -up and my blade did the same thing unless, I was assisted while pushing it up.
    I could go left or right just not up... ALL it was cable out of adjustment....
     
  17. JimRoss

    JimRoss Member
    Messages: 99

    Re-read the original post. It only does this when the fliud is warm. Once the outside temp gets below freezing, it works fine. The colder it is out, the better it would work. If it was a cable adjustment, it would be the same problem reguardless of the temp outside.

    Anyways, pump came in today. I'll see if I can find time in the next couple days to replace it. I'll report back on how/if it helps.
     
    Last edited: Nov 17, 2009
  18. Turf Commando

    Turf Commando Senior Member
    Messages: 567

    Well then you have a piece of junk ...!
     
  19. drp

    drp Senior Member
    from ontario
    Messages: 170

    Now that is uncalled for.
     
  20. drp

    drp Senior Member
    from ontario
    Messages: 170

    Well Jim I am curious did the pump fix the problem?